New to me L2250DT, broken flywheel bolts

[cviola2005]

Hello everyone, I've recently purchased a 90 or 91 model L2250DT 4wd, with front end loader and bushhog. Need repair. The story I got on the phone was that the owner got a (new to him) bushhog and was using it when something went bang. They took it apart to find the crankshaft to flywheel bolts had snapped off and the flywheel damaged. They said it had a new dual clutch setup on it. I'm not sure if they installed the new clutch setup and then things went bad, or vise versa. Not sure if they bought the clutch before finding out about the damage.

I have a replacement motor, no worries there. The only thing stumbling my thinking noodle is: "What happened to cause this problem?"

Obviously, without the owner explaining in great detail what was going on at the time, there is only speculation. And I can think of several things that could possibly have happened:

1. New clutch was not adjusted properly. I see this as on of the most likely scenarios. If the PTO clutch wasn't disengaging properly, I believe it could break something.

2. Operator was quickly engaging the clutch. Possibly THE MOST likely cause of the problem.

Initially, my first thought was that the tractor needed an overrun clutch on the back. This thought was due to the part of the story stating new (to him) bushhog was being used when it broke. In doing my research, I have learned that the dual disk clutch setup was specifically designed to combat the overrunning of implements.

Any thoughts or ideas from you folk whom are more knowledgeable of these tractors and PTO/clutch operation?

Thanks in advance.

 

[coachgeo]

Another possible issue to have caused this is running over something that stopped the blades DEAD FAST and the weakest link in the arrangement was the flywheel bolts. Which should not have been the case unless someone had swapped out the shear pin for a Grade 8 bolt (possible) . Inspect the bush hog for hints of something like this.

While tractor is separated remove cover off tranny and inspect insides to make sure something in there did not lock up and cause this. IMHO I'd inspect anything you can get too in order to eliminate as much as you can about why that happened.

 

[cviola2005]

I had thought of that as a possible cause too, but then I forgot when I started typing, lol.

Thank you for your response. I agree with you. Either case would be operator (or mechanic) error, I think.

I definitely plan to crack things open and check it all out before reassembly. Thanks for that idea. Also, good idea to check the bushhog for obvious signs of trouble.

 

[North Idaho Wolfman]

one more senerio, I don't know if it's possible to even bolt it together, but that model can be either Single clutch or Dual clutch and if parts were swapped and not all the right parts put in place that could cause some issues.

Might take a deep look at the setup!
And also if you need to get a flywheel make sure you get the right one!

Why would you have to scrap the motor?
The broken bolts should be really easy to get out of the crank.

 

[cviola2005]

I will be looking at the original parts to see what actual damage exists, but I am prepared for an engine swap just in case. If I can salvage the existing crank and flywheel , I definitely will. I'll try to get pictures when I get it apart.

I was looking at the exploded part diagram from it and saw the two different clutch setups. Looks like two completely different setups, single having one transmission input shaft, dual having two. Its a rather funky looking set up, and I can see someone messing it up when installing new clutch.

 

[D2Cat]

First thing to cross my mind is they replaced the clutch. Perhaps they misplaced the original bolts and went to the hardware store to find replacements. If softer bolts were used or original bolts not torqued tight enough, they could sheer off under pressure.

 

[rentthis]

They may have gorrilla torqued the original bolts and damaged them.

 

[North Idaho Wolfman]

The bolts on the flywheel to crank are special bolts.
If they did put in generic bolts that would explain the failure.
Another possibility that comes to mind is that they didn't line up the flywheel with the crank properly and they forced it to fit, the holes are just slightly different when they are out of sync and I could see someone doing that.

 

[cviola2005]

First thing to cross my mind is they replaced the clutch. Perhaps they misplaced the original bolts and went to the hardware store to find replacements. If softer bolts were used or original bolts not torqued tight enough, they could sheer off under pressure.

That's a good possibility that I didn't think of. I will definitely check out what remains of the bolts that I can find.

They may have gorrilla torqued the original bolts and damaged them.

Possible, especially with the WSM costing $100-$150, they very well could have just winged it on the torque.

The bolts on the flywheel to crank are special bolts.
If they did put in generic bolts that would explain the failure.
Another possibility that comes to mind is that they didn't line up the flywheel with the crank properly and they forced it to fit, the holes are just slightly different when they are out of sync and I could see someone doing that.

Ah! Another thing that I have forgotten about. The holes are not equidistant. But one question to that, aren't these engines externally balanced? So if the flywheel and crank were not oriented together correctly, that could have damaged some other things, particularly internal to the engine, right?

If the only damage is internal to the engine (including flywheel), that is ok because I have a rebuilt replacement engine. I just hope and pray that nothing is damaged elsewhere.


Thank you all for your input! Very good brainstorming! I now have several point of direction to follow, so I'm sure the investigation stage will be pretty thorough.

 

[D2Cat]

I don't think the flywheel CAN bolt to the crankshaft UNLESS the hole orientation is correct.

I always put a punch mark on the flywheel and the back side of the housing to know where to put it back. But...a couple of times I tried to rotate the FW to see if there was another combination. Close but no ringers! Bolt just wouldn't start to thread.

Wonder what other's experience has been.

 

[cviola2005]

I don't think the flywheel CAN bolt to the crankshaft UNLESS the hole orientation is correct.

I always put a punch mark on the flywheel and the back side of the housing to know where to put it back. But...a couple of times I tried to rotate the FW to see if there was another combination. Close but no ringers! Bolt just wouldn't start to thread.

Wonder what other's experience has been.

I haven't messed with this particular engine in terms of reinstalling a flywheel, but the D902 is similar. I can't remember if the bolts would catch thread or not, but I know there were 1 or 2 close possibilities, but only one true way to do it.

Maybe this scenario can be ruled out...

 

[D2Cat]

It would seem to me, if a flywheel came loose from the crankshaft while mowing....the engine RPM was up there to get to 540 PTO speed. You'd have a big hunk of weight spinning at 2200/2300 RPM, shearing bolts. You'd have a racket that would make you wonder what was coming loose. I think it could very well crack the casting on the front of the transmission. That ring gear is doing a dance in a contained area!!!!

I'd like to see the insides when you open it up.

It may all be fine. Just have to remove the bolt threads....

 

[cviola2005]

It would seem to me, if a flywheel came loose from the crankshaft while mowing....the engine RPM was up there to get to 540 PTO speed. You'd have a big hunk of weight spinning at 2200/2300 RPM, shearing bolts. You'd have a racket that would make you wonder what was coming loose. I think it could very well crack the casting on the front of the transmission. That ring gear is doing a dance in a contained area!!!!

I can only imagine the racket that it would create!

I'd like to see the insides when you open it up.

I'll try to post some pictures when I get it apart.

It may all be fine. Just have to remove the bolt threads....

I hope this is the case, no real damage... remove bolt pieces, put in new bolts, and reinstall everything

 

[cviola2005]

I haven't had the chance to work on the tractor today, but I did get it home. Here it is as it sits on the trailer.

I believe that the bushhog has too much rotational mass to be used with this tractor. So, it'll be going up for sale soon.

The previous owner got the bushhog to use with this tractor, and while using it, the tractor broke down. They brought it into the shop and tore it down to find the problem. They found broken crankshaft to flywheel bolts, and I assume just slapped it back together to roll it out of the shop while they weighed their options. They left the flywheel and dual clutch setup out of it. That's how I have a picture of it without beginning work on the tractor yet. Here is the pic showing the damage down to the flywheel by the broken bolts in the spinning crankshaft.

Looks marginal, maybe I'll put it in the lathe, and true up that surface, then make a spacer to move the flywheel back to original position so the starter and clutch work like designed. Not sure yet.

 

[whitetiger]

I don't think the flywheel CAN bolt to the crankshaft UNLESS the hole orientation is correct.

I always put a punch mark on the flywheel and the back side of the housing to know where to put it back. But...a couple of times I tried to rotate the FW to see if there was another combination. Close but no ringers! Bolt just wouldn't start to thread.

Wonder what other's experience has been.

It is impossible to install all the flywheel bolts when the flywheel is out of position. There will always be at least two bolts where the holes will not line up.

 

[coachgeo]

hopefully its just a situation where someone forgot to torque the bolts. Put them on hand tight...... got distracted and moved on.

 

[Daren Todd]

What size is the bush hog? My dad has the same model tractor with fel. With the non synchronized shuttle shift transmission. We ran a 5ft bush hog on it every summer for years with out issue Tractor is still kicking. Just has some minor electrical issues, and a leaky seal on the front end. Still on the original clutch as well

 

[cviola2005]

Coachgeo, does the flywheel have to be removed to change the clutch set?

Daren Todd, I don't know anything about the Bush hog, haven't even measured it. I'd say it's probably a 5 footer. It may not be too big for the tractor, I just threw that out there for brainstorming in hopes some one would reply with experience. Thank you for replying with experience, ruling that out as a possibility.

Thanks to others as well ruling out the possibility of the flywheel being installed not oriented correctly to the crank.

The bolts could have been loose from the clutch change, but I don't know why some one would take it off for that, except maybe to have it machined flat again?

Edit: I just remembered on of my initial thoughts, maybe the cause was operator snapping the clutch loose, when they were bushhogging?

 

[North Idaho Wolfman]

You would remove the flywheel to replace the pilot bushing or bearing, and yes like your said, if you were going to resurface the face.

 

[cviola2005]

Ah! Very good point! Be stupid not to replace pilot bearing/bushing while you're in there!

So it is very possible the bolts weren't tightened correctly after clutch install.

I sure how that was the cause, or something else operator error related.

Thanks!